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I'm from cincinnati OH, and this year i think is the last year they will have E-Check or Smog Check to some area. so as of Jan. of next year eveyone can do whatever you want to their car. I was thinking about runing a custom exhaust system with no Cat in it. What do you guy think. And it is gonna effect anything in the car?
 

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hrmm... well.. it will free up the exhaust.. but don't plan on huge power from it.

lol.. i don't think that you can do whatever you want.. as in I'm sure they don't want you removing cats.. the fine will still be there.. but , I hear what you are saying. :)
 

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Well aside from the obvious legal ramifications there are performace and noise issues.

On an NA car IMHO I think hi flo cats are better than test pipes.

But if you go for test pipes I highly suggest either buying them with resonators or if custom made have them put a resonator in them otherwise yor car will sound like ass.
 

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Etraxx posted this:

Hollowing out a catalytic converter or replacing it with a test pipe or straight section of pipe is a violation of Federal Law punishable by fines in excess of $25,000 and/or jail time for both the vehicle owner and the person doing the work.
Removing a catalytic converter will result, at most, in 5 HP in power improvement. However, hollowing out a catalytic converter will cause resonance problems. The symptom is most often seen as a hesitation, popping, or backfire at or about 3,200-3,500 RPM. Upon hard acceleration, the engine will appear to cut out for a split second as RPMs drop and a split second later recover and continue past 3,200-3,500 RPM. Additional symptoms are a loud and continual popping sound when the vehicle is allowed to decelerate under load and a whooshing sound that is delayed from or following the engine speed. This is due to the open chamber within the hollowed out catalytic converter case. It loads up and releases pressure in the exhaust system that acts almost as a capacitor. The open chamber allows the formation of standing waves within the chamber which reflects back toward the engine and causes the hesitation and miss in the RPM range.
The symptoms become more pronounced as the exhaust system is made freer flowing, meaning that hollowing out a cat with the stock exhaust may cause mild annoyance, while it becomes a serious problem when a header and performance exhaust system are installed, mimicking a ignition miss or backfire. This is probably the best reason not to hollow out a catalytic converter.
 

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Well aside from the obvious legal ramifications there are performace and noise issues.

On an NA car IMHO I think hi flo cats are better than test pipes.

But if you go for test pipes I highly suggest either buying them with resonators or if custom made have them put a resonator in them otherwise yor car will sound like ass.
I agree, here's a post on another topic from minutes ago:

I had AAM's single exhaust and test pipes added today to my NA car. WAY TOO LOUD imo!!! I've got no back pressure. It sounds mean at idle, but anything above 3,500RPM and it takes on a trumpet note. It's not what I was looking for. I'm going to put the cats back on and see how it sounds (I really like the look of the exhaust).

I'm setting the car up for FI this spring. This setup is perfect for that as the TT's will quiet the exhaust. We ordered the silencer, but I'm going to try putting the cats on first to see if they provide enough back pressure. If not, I might try test pipes with the stock exhaust.

The check engine soon light came on after driving the car from AAM home. I assume that 's because the o2 sensors recognize that the cats aren't doing there job (because they aren't there). I'm new to this, but I assume that this is the case with everyone who has test pipes. Let me know.
 
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